The present invention relates generally to a high speed imaging apparatus incorporated into a high speed video camera and a high speed video system and, more particularly, to a high speed imaging apparatus for imaging a moving picture at a high speed.
Some of high speed video cameras and high speed video systems incorporate a high speed imaging device for imaging a moving picture at a high speed. This high speed imaging device involves the use of, e.g., a solid-state imaging sensor as an imaging sensor for imaging a moving object. This solid-state imaging sensor is constructed to obtain a moving picture by sequentially making a 1-frame still picture continuous which is defined as a minimum unit for imaging.
The solid-state image sensor is arranged such that a multiplicity of photoelectric converting elements such as photo diodes are two-dimensionally arrayed to form an imaging surface, and a frame picture (still picture) is obtained by sequentially scanning the respective photoelectric converting elements combined to form this imaging surface by a predetermined scan method.
Where the photoelectric converting elements of, e.g., vertical 100 pixels.times.horizontal 100 pixels are two-dimensionally arrayed as the solid-state image sensor, 100-pixel line scanning is at first effected with respect to the first row in the vertical direction along a horizontal scan line. Upon an end of this line scanning, the line scanning along the second row is performed. Thereafter, this line scanning is sequentially executed. Upon a completion of the line scanning with respect to the 100th row, it follows that 1-frame imaging is completed.
Imaging is effected at a rate of 30 frames per second in ordinary television imaging. Hence, 3000 line scanning processes are executed for one second in the solid-state image sensor including the photoelectric converting elements in which 100 pixels are arrayed vertically and horizontally. Output signals associated with the line scanning are temporarily recorded in a VTR or a semiconductor memory, and thereafter scanning is effected at the same rate by a receiving CRT monitor, whereby a picture is reproduced and displayed.
A moving object moving at a high speed is imaged at a higher imaging rate than in the reproduction and reproduced at a normal rate of 30 frames per second. It is possible to see a motion of the moving object at a magnification given by 30 frames/imaging rate with a reduction in speed. This high speed imaging is applied to fields of physical science and engineering and sports as well. A variety of effects are exhibited.
In the television technology, a high speed imaging process is attained by increasing both the system frequency with some sacrifice of picture quality and the imaging rate. Alternatively, the high speed imaging process is attained by increasing a tape feeding speed of VTR and the number of revolutions of a video head. However, these high speed imaging methods are subject to technological restraints in terms of circuitry and mechanical aspects, wherein approximately 1000 frames per second are the limited level.
The following is a method for actualizing the high speed imaging. The imaging rate is increased by reducing the number of photoelectric converting elements provided in a solid-state image sensor and the number of vertical and horizontal pixels. According to this high speed imaging method, a high speed imaging process as high as 5000 frames per second is attainable. This method, however, presents such a defect that the screen size is diminished in inverse proportion to the imaging rate.
Proposed further is a high speed imaging method for actualizing the high speed imaging, wherein the multiplicity of photoelectric converting elements which are two-dimensionally arrayed in the solid-state image sensor are sectioned into a plurality of blocks, and the respective blocks are subjected to line scanning in parallel in the horizontal direction. According to this high speed imaging method, the imaging process as high as approximately 5000 frames per second is attainable without diminishing the screen. However, because of the respective blocks undergoing the line scanning in parallel, a plurality of amplifier circuits are simultaneously required. The circuitry becomes complicated and expensive.
The conventional high speed imaging device selects either the arrangement that a relatively high speed imaging operation is acquired by increasing the system frequency or the arrangement that the imaging speed is increased with sacrifices of the screen size and picture quality. Parallel imaging and parallel processing are needed for pursuits for increasing the imaging speed, keeping the screen size and improving the picture quality. The high speed imaging device becomes intricate and expensive.